Engine starter



. Oct. 3, 1944.

"R. H. HILL ENGINE STARTER Filed Deo. 50, 1940 4 Sheets-Sheet 1ATTORNEY,J/

Oct. 3, 1944.

R. H. HILL ENGINE STARTER Filed Deo. so, 1940 4 sheets-sheet 2 wATTORNEKd/ 0t.3, 1944. R, H. HILL 2,359,362

ENGINE STARTER Filed Deo. 50, 1940 4 Sheets-Sheet 3 M Y YJE/ ATTORNEYLOct. 3, 1944. R, H HILL 2,359,362

ENGINE STARTER Filed DGO. 50, 1940 Sheets-Sheet 4 gig. 13

Patented Oct, 3, 1944 EN STARTER Robert H. Hill, Anderson, Ind.,assignor to General Motors Corporation, Detroit, Mich., va corporation fDelaware Application December 30, 1940, Serial No. 372,369

I Claims.

This invention relates to apparatus for starting internal combustionengines, more particularly to the type of apparatus disclosed in DyerPatent 2,141,178 issued December 27, 1938. This patent discloses afriction drive between the engine to be started and the starting motor,said drive comprising a disc or annular flange associated vwith theengine fly-wheel or other member connected with the engine crank shaftand a. pair of driving discs which are engageable with opposite faces ofthe driven disc. The driving discs are interconnected by helical splinesprovided by a series 4of balls located in helical races provided byparts connected with these discs. Both driving discs are connected withthe motor armature shaft through longitudlnal splines. By manual means,both of the driving discs are moved into engagement with the driven discand the motor switch is closed. Rotation of the motor shaft forces thedriving discs against the driven disc with pressure sufficient fordriving engagement between the motor and driven disci whereby the motorwill crank the engine. When the engine becomes self operative, thepressure between the driving discs and the driven discs is automaticallyrelieved so that the/ engine will not drive the motor.

Itis an object of the present invention to improve the coaction betweenthe driving discs so that the relative movement between them in bothdirections takes place with greater freedom than heretofore. Toaccomplish this object, I provide an endless track for the balls whichcooperate with the helical races of the parts which provide the drivingdiscs. This endless track includes the helical bearing races themselvesand also an outside portion connected with the ends of the activeportions of the helical races. The balls are free to pass from thehelical races into the outside path and return again to the helicalraces Without the resistance which might be encountered in the Dyerconstruction wherein the bearing races have closed ends.

Another object of the invention pertains to the connection between thedriving discs and the driven disc provided by the flywheel. It is known,with respect to any engine starter which drives through the engineflywheel, that the starting motor operated part, pinion gear or frictionmember, will first engage the flywheel at one of several portions. For asix cylinder 4-cycle engine, there are three portions; for an eightcylinder engine, there are four. Due to the shock cation of crankingpower. these portions are subject to greater wear than other parts ofthe flywheel gear or friction disc. In the type of friction drivedisclosed herein, the unit pressure 5 between thedriving and drivendiscs is very high.

take up the shock of driving engagement due to.

the operation of the starting motor.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to. the accompanyingdrawings wherein a preferred embodiment of one form of the presentinvention is clearly shown.

In the drawings:

Fig. 1 is a side view partly in section showing a preferred embodimentof the invention in its normal condition.

Fig. 2 is a wiring diagram thereof.

Fig. 3 is a fragmentary longitudinal sectional view of the startingapparatus.

Figs. 4, 5 and 6 are sectional views taken respectively on the lines 44, 5-5 and 6 6 of Fig. 3.

Fig. 7 is a perspective view of sleeve 42.

Fig. 8 is a perspective View of driving disc 34 and parts mountedthereon.

Fig. 9 is a perspective view of driving disc 33 provided by tubularshaft 30.

Fig. 10 is a sectional view on the line lll-Ill of Fig. 11.

Fig. 11 is an assembly of the two driving disc members, the outer onebeing shown in phantom by dot-dash lines.

Figs. 12, 13 and 14 are diagrammatic views similar to Fig. 3 but showingthe mechanism in different positions of operation.

The motor 20 for starting the internal combustion engine is preferablyan electric motor comprising field frame 2| associated with an end frame22 and a housing 23 which carry bearings 24 and 25, respectively, forthe motor armature shaft 26 which carries an armature 21.

Referring now particularly to Figs. 3 to 'fthe shaft 26 carries atubular shaft 30 which is splined at 3| to the shaft 26'so that thetubular shaft 30 is at all times drivingly connected with of engagementaccompanied by the first appliu the shaft 26 but may slide thereon to a.limited v extent.

The tubular shaft 30 is urged against the end of the bearing 25 byspring 32 which surrounds the armature shaft 26 and which is locatedbetween the armature 21 and the left, hand end of the'tubular shaft 30.

The shaft 30 carries driving disc 33 and driving disc 34 adapted to moveinto engagement with and to drive a driven disc 35 having acircumferential groove 35a and connected with the flywheel of the engineto be started. The driving discs 33, 34 are so connected with each otherthat, after the driving discs have been moved against the driven disc35, rotation of the shaft 30 by the motor will cause the driving discsto be pressed against the driven disc with pressure sufficient forengine starting purposes and that, after the engine has become selfoperative, the pressure between the driving discs and driven disc willbe relieved so that the engine will not drive the starting motor whilethe engine is self operative. The driving disc 34 is connected withshaft 30 (providing disc 33) through a screw thread or helical splineconnection which is provided by a plurality of balls 38 occupying matinghelical grooves 39 and 40provided respectively by the shaft 30 and thetubular extension of driving disc 34.

The discs 33 and 34 are caused to engage driven disc 35 and the startingmotor switch is closed by manually operated means, to be describedlater. Rotation of the motor armature shaft 26 will cause the drivingdiscs to be wedged against the driven disc with a pressure sufficientfor engine starting purposes. After the engine becomes self operativeand the driven disc 35 attempts to rotate the driving discs 33 and 34faster than they can be rotated by the starting motor, the drivingpressure between the driving discs and the driven disc will be relievedso that the engine cannot drive the starting motor at excessive speed.These functions take place due to the helical spline connection betweenthe driving disc while both are being driven by the starting motor. Theembodiment of the lpresent invention includes a means independent of thestarting motor for causing the driving discs 33 and 34 to be moved intoengagement with the driven disc 35 before the starting motor operates.This means for causing a preliminary engagement of the driving discswith the driven disc will now be described.

The disc 34 has its tubular extension provided exteriorly with aplurality of helical splines 4| adapted to be engaged by the internallysplined flange 42 of a sleeve 43 which is supported by a disc 44fastened to the left end portion of shaft 30. Disc 44 is provided withrecesses 44a for receiving tangs 36a of a washer 36 having also tangs3627 received by notches 30a in tubular shaft 30. A nut 31 threaded onshaft 30 clamps washer 36 against disc 44, and the latter against ashoulder 30c of shaft 30. Thus the disc 44 is drivingly connected withshaft 30. Disc 44 has tongues 41 received by a longitudinal groove 48 ofsleeve 43. Sleeve 43 is thereby longitudinally splined to the shaft 30.Due to the great rmass of parts connected with the shaft 30 includingthe armature shaft 26 and the armature 21, the shaft 30 tends to remainstationary as the sleeve 43 iis moved longitudinally. Hence, the sleeve43 may move longitudinally without rotating substantially. The pitch ofthe splines 4| formed on the extension of disc 34 is such that, as thesleeve 43 is moved toward the left from its position shown in Fig. 3,the

disc 34 will rotate relative to the shaft 30 in a. direction such as tocause the disc 34 to move into engagement with the disc 35.

In order that the sleeve 43 may be moved toward the left from itsposition shown in Fig. 3 it is provided with an -external flange 49 forreceiving the ends 50 of a bifurcated lever 10 having at its upper endan elongated notch 1| which receives a pin 12 carnied by bifurcatedbracket 13 integral with an L-shaped bracket 14 attached to the frame15a. of a solenoid 15 mounted upon the-motor frame 2|. A spring 16surrounds a stud 11 attached to the bracket 13 and urges the upper endof the lever 10 against the pin 12.

The lever 10 is actuated electromagnetically by means which will now bedescribed with reference to Fig. 2. As shown diagrammatically in Fig. 2,magnet frame 15a encloses electromagnet windings and 8| surrounding amovable solenoid armature 82 guided by the magnet frame 15a for slidingmovement toward a stationary core 83 which is located in the magneticcircuit of the electromagnet. The armature 82 is connected by a link 84with the lever 10. Armature 82 :is associated with a rod 85 upon whichis mounted a non-conducting collar 86 yieldingly urged by spring 81.against a shoulder 88, the spring 81 being confined between the collar86 and a washer 89 held from moving toward the right by a pin 90. Aspring 9| loca-ted between a stationary .part 92 and the rod 85 normallymaintains the rod and the armature 82 in the normal position as shown inFig, 2.

The collar 36 carries a movable switch contact 95 adapted to engage withcontacts 96 and 91 of the starting motor switch. Contact 96.is connectedby wire 98 with a battery 89 grounded at 99a. Contact 91 is connectedwith the starting motor 20 which is grounded. Contact 96 is connectedwith starter solenoid relay |00 having a core |0| surrounded by coil |02and having an armature |03 attached by a spring hinge |04 to a metalbracket |05 connected with contact |05. Armature |03 carries a -contact|06 for engaging a contact |01 connected by wire |08 with terminal 19 ofsolenoid 15. Terminal 19 is connected with windings 80 and 8|, 8| beingconnected with contact 91 and 80 being rounded at |08.

The circuit of relay coil |02 includes battery 99, armature |09, wire|23, ignition switch H0, switch ||I (closed by the automobileaccelerator pedal and opened by engine intake suction when the enginebecomes self-operative), and a switch responsive to generator action andcomprising contacts ||2 and ||3. Contact H3, which is grounded, isinsulatingly supported by the armature H4 of reverse current relay H5for connecting the engine driven generator |30 with battery 99. Armature||4 is connected by spring hinge ||1 with magnet frame ||6 supporting acore ||8 surrounded by series coil I I9 and voltage coil |20. When thegenerator is charging the battery the contact |2| of armature ||4engages contact |22 (connected with wire |23) and contact ||3 isseparated from contact |I2. The control apparatus associated with lever10 causes the driving discs 33 and 34 to be moved into engagement withthe driven disc 35 before operating the starting motor 20.

The manner in which the driving discs are caused to engage the drivendiscs will now be described particularly With respect to Figs. 12, 13and 14. To start the engine the operator closes the ignition switch ||0and presses the accelerator pedal to close switch and thus connect coil|02 of solenoid relay |00 with battery 88. Relay contacts |08 and |01close and battery 38 is connected with the windings and 8| of solenoid15. The armature 82 will move toward the left thereby causing the lever10 to move to swing toward the left in a clock-wise direction around itspivot 12, During the movement of the lever 10 the contact 95 will bemoving toward contacts 96 and 91; but, before engagement of thesecontacts actually occurs, the driving discs 33 and 34 will be broughtinto engagement with the driven disc in a manner which will be apparentfrom a consideration of Figs. 12, 13 and 14.

As lever 1.0 moves toward the left the entire drive assembly Vwill bemoved bodily toward the left from the position shown in Fig. 12 to thatshown in Fig. 13 thereby causing the driving disc 33 to engage thedriven disc 35. This movement of the drive assembly is resisted by thespring 32 which normally holds the shaft 30 against the bearing 25.Further movement of the lever 10 toward the left causes the sleeve 43 tomove to the left relative to the driving disc sleeve thereby causing thedriving disc 34 to be rotated in such direction relative to the shaft 30that the disc 34 will be moved from its position shown in Fig. 13 tothat shown in Fig. 14 wherein said disc 34 engages the driven disc 35.The driving discs have now completed their preliminary movements intoengagement with the driven discs. Hence the starter drive has beenpre-conditioned for operation by the electric motor. After the drivingdiscs have completed their -preliminary movement the lower end of thelever 10 cannot move any further toward the left.

Continued motion of the solenoid armature 82 4toward the left to closecontacts 95, 96 and 91 may take place by reason of the fact -that thereis lost motion between the upper end of the lever 13 and the pivotbearing 12. Just before these contacts are closed, the spring 16 is heldby the solenoid armature 82 under compression, so that yielding pressureis applied between end of lever 10 and the sleeve flange 44, Therefore,it is only after the driving discs have been brought into engagementwith the driven discs under yielding pressure that the motor switchcontact 95 is caused to engage the stationary contacts 96 and 91. Whenthis occurs the motor 20 operates to turn the shaft 26. The winding 8|is then short circuited and winding 88 only is effective to hold themotor switch closed. Winding 80 comprises preferably a large number ofturns of fine wire and winding 8| fewer turns of coarser wire. Bothwindings are required to eiect movement of the armature 82 initiallytoward the core 83 but winding 88 only is required to maintain thearmature 82 in its attracted position. The starting motor then willoperate to cause the shaft 26 to rotate in a clockwise direction asviewed looking in the direction of arrow of Fig, 12. At the instant themotor starts to turn the shaft 26, the driving discs 33 and 34 beingthen in engagement with the driven disc 35, the first action is toincrease the pressure between the driving discs and the driven discs dueto the helical spline connection between the driving discs.

Hence the electric motor is drivingly connected when the motoris causedto operate it produces' noiselessly a pressure between the driving anddriven discs sufficient for engine starting purposes.

When the enginerbecomes self operative and attains a speed such that thelinear speed of the driven disc 35 as effected by the engine exceeds thelinear speed of the driving discs 33 and 34 as effected by the startingmotor. driving engagement between the driving and driven discs of thestarter drive is automatically released. This is accomplished that dueto the fact that as the driven disc 35 tends to run ahead of the drivingdiscs 33 and 34 these driving discs tend to unscrew themselves fromengagement with the driven disc 35. After the engine starts the solenoid15 is automatically deenergized by the open- A ing of the automaticengine-suction responsive switch and by the separation of contacts ||2and I3 when relay |I5 closes its contacts |2| and |22 to connectgenerator |30 with battery 88. The spring 9| is then released to effectmovement of the parts 85, 82, 84 and 10 toward the right as viewed inFig. 2. The spring 16 will also be released so as to move the upper endof the lever 10 toward the right returning it to its normal position. Inthis way the engine starter drive parts are restored to normal positionas shown in Figs. 1, 2, 3 and 12.

The ends 50 of lever 10 bear yleldingly upon the sleeve flange 49 andthe internal flange 42 of sleeve 43 will bear yieldingly against thehelical splines 4| of the tubular extension of driving disc 34.Therefore, since the sleeve 43 is yieldingly urged toward the left thedriving disc 33 will be yieldingly urged against the driven disc 35;and, since the driving disc 34 is caused to rotate by the sleeve 43under the action of yielding pressure, the driving disc 34 will beyieldingly pressed against the driven disc 35. Therefore both drivingdiscs are urged by means independent of the motor against the drivendisc with yielding pressure. This is desirable for the purpose ofcompensating for wear of the friction surfaces of the driving and drivendiscs.v There is another purpose which is important. If the engineshould make a weak or false start and fail to attain a speed sullicientto insure self operation, the spring 16, being then held under pressuregreater than normal by the electromagnet, an actuating force is therebystored in the spring 16 which tends to maintain the preliminary contactbetween the driving discs and the driven disc so that, if there is anytendency to relieve pressure between the driving and driven discs duringa false or weak start of the engine, this tendency will be counteractedby the tendency of the spring 16 to urge the driving discs almostinstantaneously back into cooperative relation with the driven discs. Inother words, the spring 16 forms a function analogous to that performedin the conventional one way or overrunning clutch 'by the springs whichare provided each for urging a clutch roller into wedging engagementbetween the clutch cam and the clutch shell. 'Ihus when the engineattempts to start on its own power and tends to release the drivingengagement between the driving and driven discs and then fails to attaina speed sufficient to maintain self operation. thestarting motor driveis at all times ready to pick up the load of cranking the engineinstantaneously.

The electromagnetic means which operates independent of the motor tocause the driving discs to be pressed against the driven discs beforethe motor is operated is not only a convenient means for preconditioningthe starter drive but is oneactuating forces which are required. Atilrst the attraction upon the solenoid armature 82 is relatively smallbut the force required to move the driving disc 33 toward the left isrelatively small. As the solenoid armature 82 approaches the core 83 theattraction increases greatly to give the necessarily greater forcerequired to move the driving disc 34 against the driven disc 35 and tocompress the spring 18 beyond its initial state. It is also necessarythat the starter switch contactA 95 be pressed against the stationarycontacts 96 and 91 with a pressure sufllcient to insure a goodelectrical contact. The electromagnet is also well adapted to give thisfinal pressure which is needed between the starter contacts in thestarter switch. During nal movement of the solenoid armature 82 towardthe left when the air gap between the armature and core is closing upthe pull upon the armature increases tremendously and is sufilcient notonly to effect the desired movements of the engine starter drive butalso to compress the spring 81 beyond its initial state of compressionand to force movable contact 95 firmly against the stationary contacts96 and 91.

'I'he electromagnet is so constructed as to effect a pull on thearmature 82 suillcient to make good electrical contact between thecontacts in the starter switch. The magnetic pull required for'closingthe switch properly is greater than that sumcient for preconditioningthe engine starter drive prior to actual operation of the motor.

l As undue pressure between the driving discs and the driven disc priorto operation of the motor is as undesirable as insuillcient pressure,the spring 15 operates while the motor switch is closed to limit theforce which can be applied by the electromagnet to the shifting lever10. The spring 15 is so designed that, upon being deflected a certaindistance by the amature 82 when closing the motor switch, the springwill exert the proper force upon the lever 10 tending to rotate itclockwise about its pivotal connection with the link 84. In this way thespring 16 operates not only as a spring exerting yielding pressure uponthe shifting collar flange 49 for the purposes herein specified butspring 15 operates also as a means for limiting the amount of pressurewhich can be ellected by the electromagnet.

As relative movement between the driving discs 33 and 34 must take placewith the greatest possible freedom, if the ultimate in reliability is tobe attained, the helical races 39 and 40 for the balls 38 do notterminate in closed ends as in the Dyer patent but are in communicationwith an outer track, thereby providing an endless race for the balls. Asleeve 50a is press-fitted over the member 34 and against a shoulder 34athereof and is attached to said member by a pin 5|. To the member 34(Fig. 10) is attached a scoop 52 by welding at 53 to direct the balls 38from races 39 and 40 into a straight passage 54 leading into a helicalpassage 55 provided by sleeve 50a. The passage 55 is enclosed by a tube53 pressed around sleeve 50a. The right end (Fig. 11) of helical passage55 is connected by straight passage 51 with the races 39 and 40. A scoop53 (Fig. 10) similar to scoop 52 directs the balls 38 from races 39 and4U into passage 51. As the scoops 52 and 58 project inwardly from part34, it is necessary to provide part 30 with clearance notches 30D (Fig.11) in order that part 34 may be assembled with part 30 before the balls38 are added. The balls 38 are then assembled into the endless track andthe tube 56 is pressed around the part 50a.

The driven disc 35 is diyidd by annular groove 35a into two flexibleannular flanges which yield under the pressure applied by driving discs33 and 34 and thus take up all of the shock of engagement by the drivingdiscs and substantially reduce wear on these discs.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsvmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

l. An engine starter drive comprising aligned discs located on oppositesides of a driven disc provided by a flange on the flywheel of theengine to be started and movable axially into engagement therewith, astarting motor, a longitudinallymovable shaft driven thereby andconnected with the discs, a helical spline connection between the discscomprising Iballs located in helical races provided by elementsassociated with the discs and an outer track provided by a memberassociated with one of the discs and communicating with the ends of theactive portions of the helical races.

2. An engine starter drive comprising aligned discs located on oppositesides of a drive disc provided by a flange on the flywheel of the engineto be started, said flange being divided by an annular groove in orderto provide flexibility, means for causing the discs to move axially intoengagement with the flywheel flange, a starting motor for driving thediscs, and means interconnecting the discs and responsive to the turningof the discs by the motor for causing the discs to grip the flange 4withpressure sufilcient for engine cranking purposes, the split flangeyielding under said pressure thereby reducing wear of the flangeespecially where the driving discs first engage it.

3. An engine starter drive comprising a plurality of driving discspositioned on opposite sides of a driven disc provided by a flangeformed on the flywheel of the engine, a starting motor having a, drivingshaft for operating the driving discs, means for effecting engagement ofthe driving discs with the driven disc and enabling the operation ofsaid driving discs by the starting motor, said means including aplurality of sleeves carried by the motor shaft and supporting thedriving discs, said sleeves being relatively movable longitudinally androtatively, a helical spline connection between the sleeves comprising ahelastasea ical ball race formed in the sleeves and containing aplurality of balls and means to form an endless track for said ballscomprising a passage connecting with said ball race at separated points,so that the balls can move around the endless track and friction isreduced.

4. An engine starter drive comprising a plurality of driving discspositioned on opposite sides of a driven disc provided by a flangeformed on the flywheel of the engine, a starting motor having a drivingshaft for operating the driving discs, means for eecting engagement ofthe driving discs with the driven disc and enabling the operation ofsaid driving discs by the starting motor, said means including aplurality of sleeves carried by the motor shaft and supporting thedriving discs, lsaid sleeves being relatively `mov able longitudinallyand rotatively, a helical spline connection between the sleevescomprising a helical ball race formed in the sleeves and containing aplurality of balls, a member carried by one of said sleeves and having achannel formed therein which is arranged to connect with said bail raceat separated points, so as to form an endless track through which theballs may move continuously.

5. An engine starter drive comprising a plurality of driving discspositioned on opposite sides of a driven disc provided by a flangeformed on the flywheel of the engine, a starting motor having a drivingshaft for operating the driving discs, means for eiecting engagement ofthe driving discs with the driven disc and enabling the operation ofsaid driving discs by the starting motor, said means including aplurality of sleeves l carried by the motor shaft and supporting thedriving discs, said sleeves being relatively movable longitudinally androtatively, a helical spline connection between the sleeves comprising ahelical ball race formed in the sleeves and containing a plurality ofballs, a member carried by one oi said sleeves and having a channelformed therein which is arranged to connect with said ball race atseparated points, so as to form an endless track through which the ballsmay move continuously, and guiding means associated with the ball raceto guide said balls into the channel formed in said member.

6. An engine starter drive comprising a plurality of driving discspositioned on opposite sides of a driven disc provided by a fiangeformed on the flywheel of the engine, a starting motor having a drivingshaft for operating the driving discs, means for effecting engagement ofthe driving discs with the driven disc and enabling the operation ofsaid driving discs by the starting motor, said means including aplurality of concentric and adjacent sleeves carried by the motor shaftand supporting the driving discs, said sleeves being relatively movablelongitudinally and rotatively, a helical spline connection between thesleeves comprising a helical ball race formed in the adjacent surfacesof the said sleeves and containing a plurality of balls, a sleevesupported on the outside sleeve of said concentric sleeve and having achannel formed therein which is arranged to connect with said ball raceat separated points so as to form an endless track through which theballs may move continuously, in order to reduce friction.

'7. An engine starter drive comprising a plurality of driving discspositioned on opposite sides of a driven disc provided by a flangeformed on the flywheel of the engine, a starting motor having a. drivingshaft for operating the driving discs, means for effecting movement ofsaid driving discs into engagement with said driven disc and foroperating saiel"driving discs to rotate the driven disc after engagementof the driving discs therewith, said driven disc being divided into twoparts by an annular groove in order to prevent damage to the surface ofsaid driven disc by repeated engagement of the driving discs therewith,said annular groove permitting movement of the parts of said driven disctoward each other when engaged by the driving discs so as to preventdamage to the surface with which the driving discs engage.

ROBERT H. HILL.

